1. Field of Invention
Some embodiments of the present invention generally relate to lighting systems. More specifically, some embodiments of the present invention relate to LED and other solid-state lighting fixtures and devices.
2. Background
In many sports, such as baseball, football, and golf, sometimes the ball will be high in the air, requiring good illumination in order for players and spectators to be able to see the ball. This is not a problem for daylight play. Neither is it too hard for night-time play using conventional lighting luminaires using e.g. HID light sources such as 10, FIG. 1. Conventional luminaires tend to spill a lot of light (i.e., emit light in a direction not specifically aimed at the field), sufficient to provide uplighting in area 50, high above the ground. Thus there has been very little need to design lights for uplighting, or to verify that sufficient uplighting has been made available. However, with advances in lighting control, and especially with the increasing popularity of LEDs for sports lighting, the amount of spill light is continually being reduced. The result is that the amount of light available in area 50 may be significantly reduced.
This means that there is now a significant concern in the industry to design for uplighting, both in terms of amount of light provided and in terms of other characteristics such as spectral power distribution of the uplighting. There is therefore also a need to be able to verify that the lighting installations as built meet the design specifications. And there is still further a need to be able to verify that the uplighting that is provided is of sufficient quality to meet the needs for play.
While changes from conventional lighting have raised concerns for uplighting, at the same time, the limitations of conventional lighting with regards to their spectral power distribution (SPD) have long been recognized. Although it is known that changing the SPD of light can sometimes improve contrast for sports objects, grass on the field, etc., it typically is not feasible to try to adjust SPD. But with the increasing use of LED lighting, there is an opportunity for varying SPD of downlighting and uplighting by LED luminaire design and operation techniques. This means that there is now an opportunity, with verification of lighting quality, to verify and optimize SPD of LED lighting systems for specific purposes.
There is yet even further a need to verify the quality of uplighting in a timely fashion. Since remedying such a problem is very difficult and time consuming, it is very important to determine uplighting quality prior to actual use for games, rather than simply waiting for players to discover that uplighting is not sufficient.
Additionally, it is necessary to provide the purchasers of a lighting system adequate assurance that the lighting performance they are purchasing is actually being provided. This assurance may be provided either visually or by means of measurement. Both are important, since some customers will only be satisfied by what their own eyes can see, while other customers will not be satisfied unless they receive a scientific report of lighting levels.
There is, therefore, room for improvement in the art.